1. Field of the Invention
The invention relates to an improved fuel supply system for an internal combustion engine.
2. Description of the Prior Art
German Patent Disclosure DE 102 20 281 A1 describes a fuel system for an internal combustion engine, in which fuel is pumped from a prefeed pump to a high-pressure pump and from there into a high-pressure fuel rail. A plurality of injectors are connected to this rail and inject the fuel directly into combustion chambers of the engine. The feed quantity of the high-pressure pump that is mechanically driven by the engine is determined by an upstream throttle device. To limit the production costs, the throttle device is designed such that even in the completely closed state, it allows a certain leakage quantity of fuel to pass through. This quantity is returned to a low-pressure region via a zero-feed line, in which there is a zero-feed throttle restriction, and thus does not reach the actual piston pump.